I think the problem is rather that they destroy crops than insurance; farmers probably can't grow crops in time before another swarm destroy them. As for stopp

I think the problem is rather that they destroy crops than insurance; farmers probably can't grow crops in time before another swarm destroy them. As for stopping them, I would try covering a wide enough area with a giant electric net (just like those insects killers) also placing additional screening nets on the upper and lower side so that the screens would keep birds away, and the actual electric net would have its holes large enough so that smaller insects would remain mostly untouched. The idea is that if they're stupid enough, they will eat all crops in vicinity then eventually die attempting to attack the only remaining field.